An on-board unit that orients a location of a vehicle on the basis of signals received from satellites is known. The on-board unit performs charging processing when it is determined that a corresponding vehicle travels on a toll road on the basis of acquired positional information (for example, see Patent Literature 1). In such a charging system, entrance and exit management is not performed at an entrance or an exit of the toll road but the charging processing is performed on a target vehicle travelling in a charging area. Accordingly, when a target vehicle travels in a charging area but an on-board unit thereof is detached therefrom at a time of performing the charging processing, a toll cannot be collected. When an on-board unit of a vehicle traveling in a charging area is replaced with an on-board unit of another vehicle, a regular fee cannot be collected.
A technique of recognizing a vehicle number from an image acquired by photographing a vehicle traveling on a toll road and identifying the vehicle traveling on the toll road is known (for example, see Patent Literature 2). A violating vehicle which is travelling on a toll road but intends to avoid payment of a regular fee can be identified using this technique.